Thomas P. Goonan found out the hard way how deep that Detroit-born feud runs when he got up on a stool during a May 8 ICP gig and waved an Eminem T-shirt at the band and tossed M&M candies onto the stage at the Ranch Bowl in Omaha.

Predictably – to any fan of either act except perhaps Goonan – the gesture garnered a reaction similar to that of a matador waving a red cape in front of a bull.

The hapless concert-goer was quickly escorted out of the club and into the parking lot where he found himself face-to-face with a member of ICP’s entourage, who proceeded to choke him unconscious, according to the Omaha World-Herald.

The ICP associate, identified by the paper as William B. Dail, was arrested and booked by the Omaha Police Department on a single charge of misdemeanor assault. He was released after posting a $1,000 bond. Goonan, a local waiter, suffered only minor injuries.

“I didn’t realize how deep-seated the feud between Eminem and those guys was,” Goonan told the World-Herald.

Well, duh.

Not only is the feud almost the stuff of legend, but Dail is the brother of fellow ICP associate Douglas Dail, whom Eminem is famously alleged to have pulled a gun on in a Royal Oak, Mich., parking lot last summer.

A Ranch Bowl employee told the World-Herald that when Goonan held up the offending shirt, one of the rappers entered the crowd and started pointing.

“All of a sudden, I saw a guy jump over the barricade from the backstage into the crowd,” Ranch Bowl production manager Aaron Craig told the paper.

Goonan said the same person was the one who escorted him by the elbow to the parking lot, where he met up with Dail. According to his account, Dail asked him if he wanted to start something, and then grabbed him by the neck.

“I remember putting my hand up and trying to pull his hands off,” Goonan said. “When I came to, I was on the ground.” Once free, Goonan reported the incident to police officers at a nearby convenience store.